MVs should validate gc grace seconds on the tables involved

For correctness reasons (potential resurrection of dropped values), batchlog entries are TTLs with the lowest gc grace second of all the tables involved in a batch.

It means that if gc gs is set to 0 in one of the tables, the batchlog entry will be dead on arrival, and never replayed.

We should probably warn against such LOGGED writes taking place, in general, but for MVs, we must validate that gc gs on the base table (and on the MV table, if we should allow altering gc gs there at all), is never set too low, or else.